ClientProperties.getBrowserWidth() always returns -1

[smallufo]

I want to get width of the browser.

in Application.init() , I add :
getApplicationSettings().setUploadProgressUpdatesEnabled(true);

And in a WebPage , I add :
logger.info("init . width = {}", new
WebClientInfo(getRequestCycle()).getProperties().getBrowserWidth());

but it always return -1


I found no usage for *WebClientInfo.setBrowserWidth()* in the whole wicket
6.19.0

Is it a bug ?